<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>
<body>
  <script>
    let Language = Number(prompt('请输入您的分数'))
    if(Language >= 90){
      alert('A')
    } else if(Language >= 80 && Language < 90){
      alert('B')
    } else if(Language >= 70 && Language < 80){
      alert('C')
    } else if(Language >= 60 && Language < 70){
      alert('D')
    } else {
      alert('E')
    }
  </script>
</body>
</html>